The macroexpander will then "stupidly" rerun against the code, over and over again, until there are no more macros to expand.

But the way Lisp compilers deal with recursive macros is to not allow them. From the Common Lisp spec:

"All macro and symbol macro calls appearing in the source code being compiled are expanded at compile time in such a way that they will not be expanded again at run time."

That rules out recursive macros. I think they're allowed when Lisp is being interpreted, but you should probably just not use them.

  arc> (= foo (table))
  #hash()
  arc> (= ('bar foo) 42)
  Error: "Can't set reference  bar #hash() 42"
  arc> (= foo!bar 42)
  42

  arc> (= ((foo (quote bar)) (quote baz)) 42)
  42
  arc> (= (foo!bar 'baz) 42)
  Error: "Can't invert  ((foo (quote bar)) (quote baz))"

   (def expand-metafn-call (a b) (cons a b))

The problem appears to be that the current '= was meant for use with the older ssyntax, which supports only : for composition. I'll take a better look maybe later, I'm just home from work, cooling off (very hot in the philippines right now)

The "invert" thing is really confusing, I didn't add docstrings to all the '= related stuff because of that. Me, I say refactor '=. LOL

Edit: Fixed on the git.

  (def metafn (x)
    (set x (ssyntax x))
    (and (acons x) (in (car x) 'compose 'complement)))

Same with defop. Accessing the GET/POST arguments to an operation is done via (arg req "foo"). It would have been worlds nicer if I could just define something like

  (defop foo-getter req
   (w/args (foo bar) req)
     (...))

  (def xexp (x (o indent 0))
    (if acons.x
        (withs ((tg . lst) x
	        atts nil
	        pad (apply string (n-of indent " "))
  	      pretty (all acons lst))
  	(and lst (acons caar.lst) (= atts pop.lst))
  	(string pad 
  		"<" 
  		tg 
  		(tostring:map [pr " " car._ "=\"" cdr._ "\""] atts) 
  		">" 
  		(when pretty
  		  "\n")
  		(apply string (map [xexp _ (+ indent 3)] lst)) 
  		(when pretty
  		  pad)
  		"</" 
  		tg 
  		">\n"))
        string.x))

Example:

  (xexp '(ying (foo ((bar . baz)) "zing") (yang)))

  <ying>
     <foo bar="baz">zing</foo>
     <yang>
     </yang>
  </ying>

...

...

...

Doesn't look like there's enough East Coasters to maintain interest in this- Maybe another year :)

For me, it's way too early to tell whether Arc is worth a significant investment in time or not. The potential seems be there, but the actuality could be different.

PG is not really a big fan of consistency. I think his reasoning is that consistency is another word for duplication and if you have it you're probably not using the most concise definition of your problem. I think this explains the inconsistencies in srv.arc. I suspect, as time goes on, this file will become smaller and cleaner as pg refactors it- However, I doubt it will become more "consistent".